Method for packaging organic light emitting display with frit seal and reinforcing structure

ABSTRACT

Disclosed is a method for packaging an organic light emitting display having a reinforcing member between a first substrate and a second substrate by rolling a roll retaining a curable material on non-pixel regions of unit display panels. Organic light emitting pixel arrays are formed at a plurality of pixel regions of a first mother substrate. A frit is formed at a position of a second mother substrate corresponding to the non-pixel regions of the first mother substrate. The mother substrates are coalesced to each other and sealed by the frit. The first and second mother substrates are cut into unit display panels. The unit display panels are aligned. The curable material is coated at a side the unit display panels and cured to form the reinforcing member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2006-0016856, filed on Feb. 21, 2006, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference in its entirety. This application is related to andincorporates herein by reference the entire contents of the followingconcurrently filed applications:

        Application Title Filing Date  No. ORGANIC LIGHT-EMITTINGDISPLAY Sep. 29, 2006 11/541,055 DEVICE AND METHOD OF FABRICATING THESAME ORGANIC LIGHT-EMITTING DISPLAY Sep. 29, 2006 11/529914 DEVICE ANDMETHOD OF MANUFACTURING THE SAME ORGANIC LIGHT EMITTING DISPLAY Sep. 29,2006 11/541139 DEVICE ORGANIC LIGHT-EMITTING DISPLAY Sep. 29,2006 11/541047 DEVICE WITH FRIT SEAL AND REINFORCING STRUCTURE ORGANICLIGHT EMITTING DISPLAY Sep. 29, 2006 11/540150 DEVICE METHOD OFFABRICATING THE SAME ORGANIC LIGHT EMITTING DISPLAY Sep. 29,2006 11/541009 AND METHOD OF FABRICATING THE SAME ORGANIC LIGHT-EMITTINGDISPLAY Sep. 29, 2006 11/540151 DEVICE WITH FRIT SEAL AND REINFORCINGSTRUCTURE BONDED TO FRAME METHOD FOR PACKAGING ORGANIC Sep. 29,2006 11/529910 LIGHT EMITTING DISPLAY WITH FRIT SEAL AND REINFORCINGSTURUTURE ORGANIC LIGHT-EMITTING DISPLAY Sep. 29, 2006 11/540008 DEVICEAND THE PREPARATION METHOD OF THE SAME ORGANIC LIGHT EMITTING DISPLAYSep. 29, 2006 11/541048 AND FABRICATING METHOD OF THE SAME ORGANICLIGHT-EMITTING DISPLAY Sep. 29, 2006 11/541021 AND METHOD OF MAKING THESAME ORGANIC LIGHT EMITTING DISPLAY Sep. 29, 2006 11/540024 ANDFABRICATING METHOD OF THE SAME ORGANIC LIGHT EMITTING DISPLAY Sep. 29,2006 11/529995 DEVICE AND MANUFACTURING METHOD THEREOF ORGANICLIGHT-EMITTING DISPLAY Sep. 29, 2006 11/540157 DEVICE AND MANUFACTURINGMETHOD OF THE SAME ORGANIC LIGHT EMITTING DISPLAY Sep. 29,2006 11/540149 AND FABRICATING METHOD OF THE SAME ORGANIC LIGHT EMITTINGDISPLAY Sep. 29, 2006 11/529916 AND METHOD OF FABRICATING THE SAMEORGANIC LIGHT EMITTING DISPLAY Sep. 29, 2006 11/529891 DEVICE METHOD OFFABRICATING THE SAME ORGANIC LIGHT EMITTING DISPLAY Sep. 29,2006 11/540103 AND METHOD OF FABRICATING THE SAME

BACKGROUND

1. Field of the Invention

The present invention relates to organic light emitting display devices,and more particularly for packaging of the device.

2. Discussion of Related Art

In recent years, organic light emitting displays have been widely usedand are relatively simple. The organic light emitting display isreferred to as an organic light emitting device, and is an emissivedevice using an organic layer as an emission layer. Since the organiclight emitting display can eliminate need for a back light as requiredin a liquid crystal display, it can be made thin and light weight. Thus,the organic light emitting display has been actively developed as adisplay panel in a portable information terminal such as mobilecomputer, portable telephone, portable game device, and electronic book.

In general, the organic light emitting display has a structure in whichat least one organic layer having an emission layer is interposedbetween a pair of electrodes, namely, a first electrode and a secondelectrode. The first electrode is formed on a substrate, and functionsas an anode to inject holes. An organic layer is formed at an upperportion of the first electrode. The second electrode is formed on theorganic layer to face the first electrode, and functions as a cathode toinject electrons.

When moisture or oxygen from ambient environment is introduced in adevice, the life of such an organic light emitting display is reduced,emission efficiency is deteriorated, and emission color changes due tooxidation and peeling.

Therefore, in manufacturing the organic light emitting display, it iswell known that the device is separate and sealed from an outside toprevent moisture from infiltrating into it. In the sealing method, afterorganic macromolecule such as polyester (PET) is laminated at an upperportion of the organic light emitting display, or a cover or a cap isformed by a glass or a metal having absorbent, the inside thereof isfilled with nitrogen gas. Then, edges of the cover or the cap arecapsule-sealed by a sealant such as epoxy.

However, it is impossible for the conventional method to prevent theintroduction of device destructive factors such as moisture or oxygenfrom an outside by 100%. Consequently, a structure of the device isdisadvantageous to be applied to an active surface emitting type organiclight emitting display weak to moisture, and a process to embody such amethod is complicated. In order to solve the aforementioned problems, acapsule sealing method is devised to enhance an adhesion between adevice substrate and a cap using a frit as a sealant. U.S. Pat. No.6,998,776 B2 discloses a structure of sealing an organic light emittingdisplay by coating a frit at a glass substrate.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

An aspect of the invention provides a method for making an organic lightemitting display device, which may comprise: providing first and seconddevices, each device comprising: a first substrate comprising a firstside surface, a second substrate comprising a first side surface andopposing the first substrate, an array of organic light emitting pixelsinterposed between the first and second substrates, a frit sealinterposed between the first substrate and the second substrate whilesurrounding the array, wherein the frit seal, the first substrate andthe second substrate together define an enclosed space in which thearray is located, the frit seal comprising a first side surface, and afirst side comprising the first side surfaces of the first substrate,second substrates and the frit seal; arranging the first and seconddevices such that the first substrate of the first device opposing thefirst or second substrate of the second device and that the first sidesof the first and second devices face substantially the same direction;applying a material onto the first sides of the first and seconddevices, the material being configured to form a reinforcing structurewhen cured; and curing the material so as to form a reinforcingstructure comprising a first portion contacting the first side of thefirst device and a second portion contacting the first side of thesecond device.

In the foregoing method, arranging may comprise providing a holderconfigured to hold the first and second devices, and holding the firstand second devices such that the first substrate of the first deviceopposing the first or second substrate of the second device and that thefirst sides of the first and second devices face substantially the samedirection. Applying the material may comprise causing a medium retainingthe material to contact the first sides of the first and second devices.Applying may comprise sliding the medium on the first sides of the firstand second devices. The material may be applied while holding the firstand second devices together. The medium may comprise a brush. The mediummay be arranged with a roll comprising a rotatable cylinder, and whereinapplying may comprise rolling the roll over the first sides of the firstand second devices while contacting at least part of the first sides.

Still in the foregoing method, the first substrate, the second substrateand the frit seal in combination may form a gap space outside theenclosed space in each of the first and second devices, and wherein atleast part of the material may enter into the gap space. Applying thematerial may comprise causing the material to enter into the gap space.At least part of the material entering into the gap space mayspontaneously move toward the frit seal. The gap space may have a depthfrom the first side surface of the first substrate to the first sidesurface of the frit seal, and wherein the depth may be from about 0.3 mmto about 0.7 mm. The distance between the first and second substrates inthe gap space may be from about 2 μm to about 30 μm.

In the foregoing method, applying the material may comprise causing thematerial to contact at least part of the first side of the first deviceand at least part of the first side of the second device. Applying thematerial may comprise causing the material to contact the first sidesurface of the frit seal in each of the first and second device. Thematerial may have a viscosity less than about 200 cp. Arranging maycomprise placing an insert between the first substrate of the firstdevice and the first or second substrate of the second device. Arrangingmay comprise contacting the first substrate of the first device with thefirst or second substrate of the second device.

Still in the foregoing method, the first substrate of the first deviceis arranged substantially parallel to the first or second substrate ofthe second device. The first side surface of the frit seal may besubstantially parallel to the first side surface of the first substrate.The first portion may contact the frit seal of the first device. Thefirst portion may contact at least one of the first and secondsubstrates. The first and second portions are integrated after curing.The method may further comprise separating the first portion from thesecond portion. Each of the first and second devices comprises a secondside comprising second side surfaces of the first substrate, the secondsubstrate and the frit seal, wherein the method may further compriseapplying the material with the second sides of the first and seconddevices. The medium may move in a direction when applying the material,and wherein an angle between one of the substrates of the first andsecond devices and the direction of the movement may be about 5 to 90degrees when forming the mass of the material. The medium may move in adirection when applying the material, and wherein an angle between oneof the substrates of the first and second devices and the direction ofthe movement may be about 10 to about 89 degrees when forming the massof the material.

The foregoing method may further comprising providing at least oneadditional device comprising a first substrate comprising a first sidesurface, a second substrate comprising a first side surface and opposingthe first substrate, an array of organic light emitting pixelsinterposed between the first and second substrates, a frit sealinterposed between the first substrate and the second substrate whilesurrounding the array, wherein the frit seal, the first substrate andthe second substrate may together define an enclosed space in which thearray is located, the frit seal comprising a first side surface, and afirst side comprising the first side surfaces of the first substrate,the second substrates and the frit seal, wherein arranging may furtherarrange the at least one additional device together with the first andsecond devices, wherein applying may further apply the material on theat least one additional device, and wherein curing may form at least oneadditional structure, each of which contacts the first side of each ofthe at least one additional device. The frit seal may comprise one ormore materials selected from the group consisting of magnesium oxide(MgO), calcium oxide (CaO), barium oxide (BaO), lithium oxide (Li₂O),sodium oxide (Na₂O), potassium oxide (K₂O), boron oxide (B₂O₃), vanadiumoxide (V₂O₅), zinc oxide (ZnO), tellurium oxide (TeO₂), aluminum oxide(Al₂O₃), silicon dioxide (SiO₂), lead oxide (PbO), tin oxide (SnO),phosphorous oxide (P₂O₅), ruthenium oxide (Ru₂O), rubidium oxide (Rb₂O),rhodium oxide (Rh₂O), ferrite oxide (Fe₂O₃), copper oxide (CuO),titanium oxide (TiO₂), tungsten oxide (WO₃), bismuth oxide (Bi₂O₃),antimony oxide (Sb₂O₃), lead-borate glass, tin-phosphate glass, vanadateglass, and borosilicate.

Another aspect of the present invention provides a method formanufacturing an organic light emitting display, which fill areinforcing member at once in a liquid phase between a first substrateand a second substrate by dipping non-pixel regions of unit displaypanels in the reinforcing member.

Still another aspect of the present invention provides a method formanufacturing an organic light emitting display, comprising the stepsof: (i) forming an organic light emitting device at a plurality of pixelregions of a first mother substrate, the first mother substrateincluding the plurality of pixel regions and a plurality of non-pixelregions; (ii) forming a frit at a second mother substrate correspondingto the non-pixel regions of the first mother substrate; (iii) coalescingthe second mother substrate to the first mother substrate so that theplurality of pixel regions of the first mother substrate are sealed bythe frit; (iv) cutting the first and second mother substrates coalescedto separate the first and second mother substrates from unit displaypanels; (v) aligning the unit display panels; and (vi) coating areinforcing member at an outer side surface of each of the unit displaypanels. The reinforcing member is formed by a roll printing method.Preferably, the method further comprises a step of curing thereinforcing member after coating the reinforcing member. The reinforcingmember is cured by ultra-violet ray, natural curing, or thermal process.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 a to FIG. 1 f are cross-sectional views showing a method formanufacturing an organic light emitting display according to anembodiment of the present invention, and FIG. 1G is a schematic sideview of a plurality of organic light emitting display devices withinserts interposed between the plurality of organic light emittingdisplay devices;

FIG. 2 a to FIG. 2 f are perspective views showing a method formanufacturing an organic light emitting display according to anembodiment of the present invention;

FIG. 3A is a schematic exploded view of a passive matrix type organiclight emitting display device in accordance with one embodiment;

FIG. 3B is a schematic exploded view of an active matrix type organiclight emitting display device in accordance with one embodiment;

FIG. 3C is a schematic top plan view of an organic light emittingdisplay in accordance with one embodiment;

FIG. 3D is a cross-sectional view of the organic light emitting displayof FIG. 3C, taken along the line d-d; and

FIG. 3E is a schematic perspective view illustrating mass production oforganic light emitting devices in accordance with one embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments according to the present invention will bedescribed with reference to the accompanying drawings.

An organic light emitting display (OLED) is a display device comprisingan array of organic light emitting diodes. Organic light emitting diodesare solid state devices which include an organic material and areadapted to generate and emit light when appropriate electricalpotentials are applied.

OLEDs can be generally grouped into two basic types dependent on thearrangement with which the stimulating electrical current is provided.FIG. 3A schematically illustrates an exploded view of a simplifiedstructure of a passive matrix type OLED 1000. FIG. 3B schematicallyillustrates a simplified structure of an active matrix type OLED 1001.In both configurations, the OLED 1000, 1001 includes OLED pixels builtover a substrate 1002, and the OLED pixels include an anode 1004, acathode 1006 and an organic layer 1010. When an appropriate electricalcurrent is applied to the anode 1004, electric current flows through thepixels and visible light is emitted from the organic layer.

Referring to FIG. 3A, the passive matrix OLED (PMOLED) design includeselongate strips of anode 1004 arranged generally perpendicular toelongate strips of cathode 1006 with organic layers interposedtherebetween. The intersections of the strips of cathode 1006 and anode1004 define individual OLED pixels where light is generated and emittedupon appropriate excitation of the corresponding strips of anode 1004and cathode 1006. PMOLEDs provide the advantage of relatively simplefabrication.

Referring to FIG. 3B, the active matrix OLED (AMOLED) includeslocaldriving circuits 1012 arranged between the substrate 1002 and anarray of OLED pixels. An individual pixel of AMOLEDs is defined betweenthe common cathode 1006 and an anode 1004, which is electricallyisolated from other anodes. Each driving circuit 1012 is coupled with ananode 1004 of the OLED pixels and further coupled with a data line 1016and a scan line 1018. In embodiments, the scan lines 1018 supply scansignals that select rows of the driving circuits, and the data lines1016 supply data signals for particular driving circuits. The datasignals and scan signals stimulate the local driving circuits 1012,which excite the anodes 1004 so as to emit light from theircorresponding pixels.

In the illustrated AMOLED, the local driving circuits 1012, the datalines 1016 and scan lines 1018 are buried in a planarization layer 1014,which is interposed between the pixel array and the substrate 1002. Theplanarization layer 1014 provides a planar top surface on which theorganic light emitting pixel array is formed. The planarization layer1014 may be formed of organic or inorganic materials, and formed of twoor more layers although shown as a single layer. The local drivingcircuits 1012 are typically formed with thin film transistors (TFT) andarranged in a grid or array under the OLED pixel array. The localdriving circuits 1012 may be at least partly made of organic materials,including organic TFT. AMOLEDs have the advantage of fast response timeimproving their desirability for use in displaying data signals. Also,AMOLEDs have the advantages of consuming less power than passive matrixOLEDs.

Referring to common features of the PMOLED and AMOLED designs, thesubstrate 1002 provides structural support for the OLED pixels andcircuits. In various embodiments, the substrate 1002 can comprise rigidor flexible materials as well as opaque or transparent materials, suchas plastic, glass, and/or foil. As noted above, each OLED pixel or diodeis formed with the anode 1004, cathode 1006 and organic layer 1010interposed therebetween. When an appropriate electrical current isapplied to the anode 1004, the cathode 1006 injects electrons and theanode 1004 injects holes. In certain embodiments, the anode 1004 andcathode 1006 are inverted; i.e., the cathode is formed on the substrate1002 and the anode is opposingly arranged.

Interposed between the cathode 1006 and anode 1004 are one or moreorganic layers. More specifically, at least one emissive or lightemitting layer is interposed between the cathode 1006 and anode 1004.The light emitting layer may comprise one or more light emitting organiccompounds. Typically, the light emitting layer is configured to emitvisible light in a single color such as blue, green, red or white. Inthe illustrated embodiment, one organic layer 1010 is formed between thecathode 1006 and anode 1004 and acts as a light emitting layer.Additional layers, which can be formed between the anode 1004 andcathode 1006, can include a hole transporting layer, a hole injectionlayer, an electron transporting layer and an electron injection layer.

Hole transporting and/or injection layers can be interposed between thelight emitting layer 1010 and the anode 1004. Electron transportingand/or injecting layers can be interposed between the cathode 1006 andthe light emitting layer 1010. The electron injection layer facilitatesinjection of electrons from the cathode 1006 toward the light emittinglayer 1010 by reducing the work function for injecting electrons fromthe cathode 1006. Similarly, the hole injection layer facilitatesinjection of holes from the anode 1004 toward the light emitting layer1010. The hole and electron transporting layers facilitate movement ofthe carriers injected from the respective electrodes toward the lightemitting layer.

In some embodiments, a single layer may serve both electron injectionand transportation functions or both hole injection and transportationfunctions. In some embodiments, one or more of these layers are lacking.In some embodiments, one or more organic layers are doped with one ormore materials that help injection and/or transportation of thecarriers. In embodiments where only one organic layer is formed betweenthe cathode and anode, the organic layer may include not only an organiclight emitting compound but also certain functional materials that helpinjection or transportation of carriers within that layer.

There are numerous organic materials that have been developed for use inthese layers including the light emitting layer. Also, numerous otherorganic materials for use in these layers are being developed. In someembodiments, these organic materials may be macromolecules includingoligomers and polymers. In some embodiments, the organic materials forthese layers may be relatively small molecules. The skilled artisan willbe able to select appropriate materials for each of these layers in viewof the desired functions of the individual layers and the materials forthe neighboring layers in particular designs.

In operation, an electrical circuit provides appropriate potentialbetween the cathode 1006 and anode 1004. This results in an electricalcurrent flowing from the anode 1004 to the cathode 1006 via theinterposed organic layer(s). In one embodiment, the cathode 1006provides electrons to the adjacent organic layer 1010. The anode 1004injects holes to the organic layer 1010. The holes and electronsrecombine in the organic layer 1010 and generate energy particles called“excitons.” The excitons transfer their energy to the organic lightemitting material in the organic layer 1010, and the energy is used toemit visible light from the organic light emitting material. Thespectral characteristics of light generated and emitted by the OLED1000, 1001 depend on the nature and composition of organic molecules inthe organic layer(s). The composition of the one or more organic layerscan be selected to suit the needs of a particular application by one ofordinary skill in the art.

OLED devices can also be categorized based on the direction of the lightemission. In one type referred to as “top emission” type, OLED devicesemit light and display images through the cathode or top electrode 1006.In these embodiments, the cathode 1006 is made of a material transparentor at least partially transparent with respect to visible light. Incertain embodiments, to avoid losing any light that can pass through theanode or bottom electrode 1004, the anode may be made of a materialsubstantially reflective of the visible light. A second type of OLEDdevices emits light through the anode or bottom electrode 1004 and iscalled “bottom emission” type. In the bottom emission type OLED devices,the anode 1004 is made of a material which is at least partiallytransparent with respect to visible light. Often, in bottom emissiontype OLED devices, the cathode 1006 is made of a material substantiallyreflective of the visible light. A third type of OLED devices emitslight in two directions, e.g. through both anode 1004 and cathode 1006.Depending upon the direction(s) of the light emission, the substrate maybe formed of a material which is transparent, opaque or reflective ofvisible light.

In many embodiments, an OLED pixel array 1021 comprising a plurality oforganic light emitting pixels is arranged over a substrate 1002 as shownin FIG. 3C. In embodiments, the pixels in the array 1021 are controlledto be turned on and off by a driving circuit (not shown), and theplurality of the pixels as a whole displays information or image on thearray 1021. In certain embodiments, the OLED pixel array 1021 isarranged with respect to other components, such as drive and controlelectronics to define a display region and a non-display region. Inthese embodiments, the display region refers to the area of thesubstrate 1002 where OLED pixel array 1021 is formed. The non-displayregion refers to the remaining areas of the substrate 1002. Inembodiments, the non-display region can contain logic and/or powersupply circuitry. It will be understood that there will be at leastportions of control/drive circuit elements arranged within the displayregion. For example, in PMOLEDs, conductive components will extend intothe display region to provide appropriate potential to the anode andcathodes. In AMOLEDs, local driving circuits and data/scan lines coupledwith the driving circuits will extend into the display region to driveand control the individual pixels of the AMOLEDs.

One design and fabrication consideration in OLED devices is that certainorganic material layers of OLED devices can suffer damage or accelerateddeterioration from exposure to water, oxygen or other harmful gases.Accordingly, it is generally understood that OLED devices be sealed orencapsulated to inhibit exposure to moisture and oxygen or other harmfulgases found in a manufacturing or operational environment. FIG. 3Dschematically illustrates a cross-section of an encapsulated OLED device1011 having a layout of FIG. 3C and taken along the line d-d of FIG. 3C.In this embodiment, a generally planar top plate or substrate 1061engages with a seal 1071 which further engages with a bottom plate orsubstrate 1002 to enclose or encapsulate the OLED pixel array 1021. Inother embodiments, one or more layers are formed on the top plate 1061or bottom plate 1002, and the seal 1071 is coupled with the bottom ortop substrate 1002, 1061 via such a layer. In the illustratedembodiment, the seal 1071 extends along the periphery of the OLED pixelarray 1021 or the bottom or top plate 1002, 1061.

In embodiments, the seal 1071 is made of a frit material as will befurther discussed below. In various embodiments, the top and bottomplates 1061, 1002 comprise materials such as plastics, glass and/ormetal foils which can provide a barrier to passage of oxygen and/orwater to thereby protect the OLED pixel array 1021 from exposure tothese substances. In embodiments, at least one of the top plate 1061 andthe bottom plate 1002 are formed of a substantially transparentmaterial.

To lengthen the life time of OLED devices 1011, it is generally desiredthat seal 1071 and the top and bottom plates 1061, 1002 provide asubstantially non-permeable seal to oxygen and water vapor and provide asubstantially hermetically enclosed space 1081. In certain applications,it is indicated that the seal 1071 of a frit material in combinationwith the top and bottom plates 1061, 1002 provide a barrier to oxygen ofless than approximately 10⁻³ cc/m²-day and to water of less than 10⁻⁶g/m²-day. Given that some oxygen and moisture can permeate into theenclosed space 1081, in some embodiments, a material that can take upoxygen and/or moisture is formed within the enclosed space 1081.

The seal 1071 has a width W, which is its thickness in a directionparallel to a surface of the top or bottom substrate 1061, 1002 as shownin FIG. 3D. The width varies among embodiments and ranges from about 300μm to about 3000 μm, optionally from about 500 μm to about 1500 μm.Also, the width may vary at different positions of the seal 1071. Insome embodiments, the width of the seal 1071 may be the largest wherethe seal 1071 contacts one of the bottom and top substrate 1002, 1061 ora layer formed thereon. The width may be the smallest where the seal1071 contacts the other. The width variation in a single cross-sectionof the seal 1071 relates to the cross-sectional shape of the seal 1071and other design parameters.

The seal 1071 has a height H, which is its thickness in a directionperpendicular to a surface of the top or bottom substrate 1061, 1002 asshown in FIG. 3D. The height varies among embodiments and ranges fromabout 2 μm to about 30 μm, optionally from about 10 μm to about 15 μm.Generally, the height does not significantly vary at different positionsof the seal 1071. However, in certain embodiments, the height of theseal 1071 may vary at different positions thereof.

In the illustrated embodiment, the seal 1071 has a generally rectangularcross-section. In other embodiments, however, the seal 1071 can haveother various cross-sectional shapes such as a generally squarecross-section, a generally trapezoidal cross-section, a cross-sectionwith one or more rounded edges, or other configuration as indicated bythe needs of a given application. To improve hermeticity, it isgenerally desired to increase the interfacial area where the seal 1071directly contacts the bottom or top substrate 1002, 1061 or a layerformed thereon. In some embodiments, the shape of the seal can bedesigned such that the interfacial area can be increased.

The seal 1071 can be arranged immediately adjacent the OLED array 1021,and in other embodiments, the seal 1071 is spaced some distance from theOLED array 1021. In certain embodiment, the seal 1071 comprisesgenerally linear segments that are connected together to surround theOLED array 1021. Such linear segments of the seal 1071 can extend, incertain embodiments, generally parallel to respective boundaries of theOLED array 1021. In other embodiment, one or more of the linear segmentsof the seal 1071 are arranged in a non-parallel relationship withrespective boundaries of the OLED array 1021. In yet other embodiments,at least part of the seal 1071 extends between the top plate 1061 andbottom plate 1002 in a curvilinear manner.

As noted above, in certain embodiments, the seal 1071 is formed using afrit material or simply “frit” or glass frit,” which includes fine glassparticles. The frit particles includes one or more of magnesium oxide(MgO), calcium oxide (CaO), barium oxide (BaO), lithium oxide (Li₂O),sodium oxide (Na₂O), potassium oxide (K₂O), boron oxide (B₂O₃), vanadiumoxide (V₂O₅), zinc oxide (ZnO), tellurium oxide (TeO₂), aluminum oxide(Al₂O₃), silicon dioxide (SiO₂), lead oxide (PbO), tin oxide (SnO),phosphorous oxide (P₂O₅), ruthenium oxide (Ru₂O), rubidium oxide (Rb₂O),rhodium oxide (Rh₂O), ferrite oxide (Fe₂O₃), copper oxide (CuO),titanium oxide (TiO₂), tungsten oxide (WO₃), bismuth oxide (Bi₂O₃),antimony oxide (Sb₂O₃), lead-borate glass, tin-phosphate glass, vanadateglass, and borosilicate, etc. In embodiments, these particles range insize from about 2 μm to about 30 μm, optionally about 5 μm to about 10μm, although not limited only thereto. The particles can be as large asabout the distance between the top and bottom substrates 1061, 1002 orany layers formed on these substrates where the frit seal 1071 contacts.

The frit material used to form the seal 1071 can also include one ormore filler or additive materials. The filler or additive materials canbe provided to adjust an overall thermal expansion characteristic of theseal 1071 and/or to adjust the absorption characteristics of the seal1071 for selected frequencies of incident radiant energy. The filler oradditive material(s) can also include inversion and/or additive fillersto adjust a coefficient of thermal expansion of the frit. For example,the filler or additive materials can include transition metals, such aschromium (Cr), iron (Fe), manganese (Mn), cobalt (Co), copper (Cu),and/or vanadium. Additional materials for the filler or additivesinclude ZnSiO₄, PbTiO₃, ZrO₂, eucryptite.

In embodiments, a frit material as a dry composition contains glassparticles from about 20 to 90 about wt %, and the remaining includesfillers and/or additives. In some embodiments, the frit paste containsabout 10-30 wt % organic materials and about 70-90% inorganic materials.In some embodiments, the frit paste contains about 20 wt % organicmaterials and about 80 wt % inorganic materials. In some embodiments,the organic materials may include about 0-30 wt % binder(s) and about70-100 wt % solvent(s). In some embodiments, about 10 wt % is binder(s)and about 90 wt % is solvent(s) among the organic materials. In someembodiments, the inorganic materials may include about 0-10 wt %additives, about 20-40 wt % fillers and about 50-80 wt % glass powder.In some embodiments, about 0-5 wt % is additive(s), about 25-30 wt % isfiller(s) and about 65-75 wt % is the glass powder among the inorganicmaterials.

In forming a frit seal, a liquid material is added to the dry fritmaterial to form a frit paste. Any organic or inorganic solvent with orwithout additives can be used as the liquid material. In embodiments,the solvent includes one or more organic compounds. For example,applicable organic compounds are ethyl cellulose, nitro cellulose,hydroxyl propyl cellulose, butyl carbitol acetate, terpineol, butylcellusolve, acrylate compounds. Then, the thus formed frit paste can beapplied to form a shape of the seal 1071 on the top and/or bottom plate1061, 1002.

In one exemplary embodiment, a shape of the seal 1071 is initiallyformed from the frit paste and interposed between the top plate 1061 andthe bottom plate 1002. The seal 1071 can in certain embodiments bepre-cured or pre-sintered to one of the top plate and bottom plate 1061,1002. Following assembly of the top plate 1061 and the bottom plate 1002with the seal 1071 interposed therebetween, portions of the seal 1071are selectively heated such that the frit material forming the seal 1071at least partially melts. The seal 1071 is then allowed to resolidify toform a secure joint between the top plate 1061 and the bottom plate 1002to thereby inhibit exposure of the enclosed OLED pixel array 1021 tooxygen or water.

In embodiments, the selective heating of the frit seal is carried out byirradiation of light, such as a laser or directed infrared lamp. Aspreviously noted, the frit material forming the seal 1071 can becombined with one or more additives or filler such as species selectedfor improved absorption of the irradiated light to facilitate heatingand melting of the frit material to form the seal 1071.

In some embodiments, OLED devices 1011 are mass produced. In anembodiment illustrated in FIG. 3E, a plurality of separate OLED arrays1021 is formed on a common bottom substrate 1101. In the illustratedembodiment, each OLED array 1021 is surrounded by a shaped frit to formthe seal 1071. In embodiments, common top substrate (not shown) isplaced over the common bottom substrate 1101 and the structures formedthereon such that the OLED arrays 1021 and the shaped frit paste areinterposed between the common bottom substrate 1101 and the common topsubstrate. The OLED arrays 1021 are encapsulated and sealed, such as viathe previously described enclosure process for a single OLED displaydevice. The resulting product includes a plurality of OLED devices kepttogether by the common bottom and top substrates. Then, the resultingproduct is cut into a plurality of pieces, each of which constitutes anOLED device 1011 of FIG. 3D. In certain embodiments, the individual OLEDdevices 1011 then further undergo additional packaging operations tofurther improve the sealing formed by the frit seal 1071 and the top andbottom substrates 1061, 1002.

Occasionally, the sealing material may not completely prevent moistureor air entering into the enclosed space. Also, there may be cracks inthe sealing material and in the interfacial area where the sealingmaterial contacts the substrate for various reasons.

FIG. 1 a to FIG. 1 f are cross-sectional views showing a method formanufacturing an organic light emitting display according to anembodiment of the present invention. FIG. 2 a to FIG. 2 f areperspective views showing a method for manufacturing an organic lightemitting display according to an embodiment of the present invention.FIG. 1 a to FIG. 1 f and FIG. 2 a to FIG. 2 f illustrate an embodimentof the present invention, but the present invention is not limited tothe embodiments illustrated in FIG. 1 a to FIG. 1 f and FIG. 2 a to FIG.2 f.

Hereinafter, two display panels among a plurality of display panels thatare continuously arranged, are referred to as first display panel 120and a second display panel 130, respectively. With reference to FIG. 1 aand FIG. 2 a, at least the first display panel 120 and the seconddisplay panel 130 are formed at a first mother substrate 110 in such away that they are arranged in sequence. The first display panel 120includes a first pixel region 120 a and a first non-pixel region 120 b.The second display panel 130 includes a second pixel region 130 a and asecond non-pixel region 130 b. A second mother substrate 160 ispositioned at a lower portion of the first mother substrate 110, andcovers the first mother substrate 110. A cut line (not shown) is formedat each of the first mother substrate 110 and the second mothersubstrate 120, which separates respective display panels from eachother. For example, a cut line is formed at a boundary between the firstpixel region 120 b of the first display panel 120 and the secondnon-pixel region 130 b of the second display panel 130.

Referring to FIGS. 1 b and 2 b, in one surface of the second mothersubstrate 160, a frit 140 is coated at a part corresponding to aperipheral portion of each of the pixel regions 120 a and 130 a, whichseals at least the pixel regions 120 a and 130 a of the first mothersubstrate 110. That is, the frit 140 is coated along a peripheral regioncorresponding to the pixel regions 120 a and 130 a formed in the firstmother substrate 110. In an embodiment, the frit 140 includes a filler(not shown) and an absorbent (not shown). The filler adjusts a thermalexpansion coefficient of the frit 140. The absorbent adsorbs laser orinfrared ray. The frit 140 is made in a form of a glass powder having anoxide powder. By rapidly reducing a temperature of a heated glassmaterial, the frit 140 is formed in a glass powder pattern. Organicsubstance is added to the frit 140 to make a paste in a gel state. Then,the frit 140 is sintered at a predetermined temperature to remove theorganic substance. The frit paste in a gel state is cured to form thefrit seal 140 in a solid state. In an embodiment, preferably, atemperature of sintering the frit 140 ranges from about 300° C. to about700° C.

With reference to FIG. 1 c and FIG. 2 c, after the first mothersubstrate 110 and the second mother substrate 160 are coalesced to eachother, a laser or infrared ray is irradiated to the frit 140, therebymelting the frit 140, and then the frit is cured. Accordingly, the firstmother substrate 110 and the second mother substrate 160 are coalescedto each other. The second mother substrate 160 covers the first mothersubstrate 110, predetermined enclosed space is formed in the device andthe organic light emitting pixels are protected from external oxygen ormoisture.

Referring to FIG. 1 d and FIG. 2 d, a cutting process is performed usinga cutting machine, and then the first and second mother substrates 110and 160 coalesced is divided into respective unit display panels. Thecutting process is carried out along a cut line (not shown) formed onthe first and second mother substrates 110 and 160.

With reference to FIG. 1 e and FIG. 2 e, the divided unit display panelsor unfinished devices are aligned inside an alignment means (not shown).A slot and a partition are provided inside the alignment means to have astructure capable of receiving unit display panels. In an embodiment,the unit display panels are aligned inside the alignment means to beadjacent to each other. A first substrate of a unit display panel whichis one of aligned unit display panels and a second substrate in anotheraligned unit display panel, which is adjacent to the unit display panel,are facing each other and apart from each other. A reinforcing member150 is formed in each unit display panel, using alignment means toreduce a process time.

Herein, the alignment means is an auxiliary means to easily coat thereinforcing member 150 to be described later, and the invention is notlimited to a specific configuration thereof. Moreover, materials whichdo not have adhesive strength with the reinforcing member 150 may beused in the alignment means in order to easily separate the unit displaypanels after coating the reinforcing member.

With reference to FIG. 1 f and FIG. 2 f, the unit display panels 120 and130 aligned in the alignment means are preferably retained in a slot ora partition provided in the alignment means so that the reinforcingmaterial does not flow on a pixel region of a unit display panel duringor after the formation process of the reinforcing member 150.

Next, the reinforcing material is coated at upper portions of theretained unit display panels, and the reinforcing material is formedbetween the substrates and outside the fit 140 by using a roller 170. Inan embodiment, the reinforcing material can be formed using a rollprinting method or a simultaneous printing method. In an embodiment,such reinforcing material is made of resin syrup. Acrylate cyanide,acrylate, epoxy, acrylate and urethane acrylate may be used as thereinforcing member 150. The acrylate cyanide is a material that isnaturally cured. The acrylate is a material that is thermally cured at atemperature less than about 80° C. The epoxy acrylate and urethaneacrylate are a material that is cured by ultra-violet ray. In anembodiment, after separating the unit display panels from the alignmentmeans, ultra-violet curing, natural curing, or thermal process for thereinforcing material is performed to form reinforcing member 150.Referring to FIG. 1G, in one embodiment, an insert 180 is interposedbetween the substrates 110 and 160 of two neighboring devices.

As apparent from the above description, in accordance with the presentinvention, a reinforcing member is further formed outside the fritadhering first and second substrates to each other. This may prevent anorganic light emitting display from easily being broken or damaged dueto impact, and improve reliability of the device. Moreover, this mayperfectly protect organic light emitting pixels from the ambientenvironment. Also, after aligning or arranging a plurality of unitdisplay panels, reinforcing members are simultaneously formed.Accordingly, this method can reduce a process time as compared with amethod of forming reinforcing members one by one of respective unitdisplay panels, and therefore, the present invention extremely enhancesmass productivity of an organic light emitting display.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges might be made in this embodiment without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. A method for making an organic light emitting display device, themethod comprising: providing first and second devices, each devicecomprising: a first substrate comprising a first side surface and afront surface, a second substrate comprising a first side surface and arear surface and opposing the first substrate, wherein the front andrear surfaces face away from each other, an array of organic lightemitting pixels interposed between the first and second substrates, adisplay surface configured to display an image thereon, wherein thedisplay surface is at least part of at least one of the front and rearsurfaces, a frit seal interposed between the first substrate and thesecond substrate while surrounding the array, wherein the frit seal, thefirst substrate and the second substrate together define an enclosedspace in which the array is located, the frit seal comprising a firstside surface, and a first side comprising the first side surfaces of thefirst substrate, second substrates and the frit seal; arranging thefirst and second devices such that the front surface of the first deviceopposes the front or rear surface of the second device and that thefirst sides of the first and second devices face substantially the samedirection; applying a material onto the first sides of the first andsecond devices, the material being configured to form a reinforcingstructure when cured; and curing the material so as to form areinforcing structure comprising a first portion contacting the firstside of the first device and a second portion contacting the first sideof the second device.
 2. The method of claim 1, wherein arrangingcomprises: holding the first and second devices such that the frontsurface of the first device opposing the front or rear surface of thesecond device and that the first sides of the first and second devicesface substantially the same direction.
 3. The method of claim 1, whereinapplying the material while holding the first and second devicestogether.
 4. A method for making an organic light emitting displaydevice, the method comprising: providing first and second devices, eachdevice comprising: a first substrate comprising a first side surface, asecond substrate comprising a first side surface and opposing the firstsubstrate, an array of organic light emitting pixels interposed betweenthe first and second substrates, a frit seal interposed between thefirst substrate and the second substrate while surrounding the array,wherein the frit seal, the first substrate and the second substratetogether define an enclosed space in which the array is located, thefrit seal comprising a first side surface, and a first side comprisingthe first side surfaces of the first substrate, second substrates andthe frit seal; arranging the first and second devices such that thefirst substrate of the first device opposes the first or secondsubstrate of the second device and that the first sides of the first andsecond devices face substantially the same direction; applying amaterial onto the first sides of the first and second devices, thematerial being configured to form a reinforcing structure when cured;and curing the material so as to form a reinforcing structure comprisinga first portion contacting the first side of the first device and asecond portion contacting the first side of the second device, whereinapplying the material comprises causing a medium retaining the materialto contact the first sides of the first and second devices.
 5. Themethod of claim 4, wherein applying comprises sliding the medium on thefirst sides of the first and second devices.
 6. The method of claim 4,wherein the medium comprise a brush.
 7. The method of claim 4, whereinthe medium is arranged with a roll comprising a rotatable cylinder, andwherein applying comprises rolling the roll over the first sides of thefirst and second devices while contacting at least part of the firstsides.
 8. The method of claim 1, wherein the first substrate, the secondsubstrate and the frit seal in combination form a gap space outside theenclosed space in each of the first and second devices, and wherein atleast part of the material enters into the gap space.
 9. The method ofclaim 8, wherein applying the material comprises causing the material toenter into the gap space.
 10. The method of claim 9, wherein at leastpart of the material entering into the gap space spontaneously movestoward the frit seal.
 11. The method of claim 8, wherein the gap spacehas a depth from the first side surface of the first substrate to thefirst side surface of the frit seal, and wherein the depth is from about0.3 mm to about 0.7 mm.
 12. The method of claim 8, wherein the distancebetween the first and second substrates in the gap space is from about 2μm to about 30 μm.
 13. The method of claim 1, wherein applying thematerial comprises causing the material to contact at least part of thefirst side of the first device and at least part of the first side ofthe second device.
 14. The method of claim 1, wherein applying thematerial comprises causing the material to contact the first sidesurface of the frit seal in each of the first and second device.
 15. Themethod of claim 1, wherein the material has a viscosity less than about200 cp.
 16. The method of claim 1, wherein arranging comprises placingan insert between the first substrate of the first device and the firstor second substrate of the second device.
 17. The method of claim 1,wherein arranging comprises contacting the first substrate of the firstdevice with the first or second substrate of the second device.
 18. Themethod of claim 1, wherein the first substrate of the first device isarranged substantially parallel to the first or second substrate of thesecond device.
 19. The method of claim 1, wherein the first side surfaceof the frit seal is substantially parallel to the first side surface ofthe first substrate.
 20. The method of claim 1, wherein the firstportion contacts the frit seal of the first device.
 21. The method ofclaim 1, wherein the first portion contacts at least one of the firstand second substrates.
 22. method of claim 1, wherein the first andsecond portions are integrated after curing.
 23. method of claim 22,further comprising separating the first portion from the second portion.24. The method of claim 1, wherein each of the first and second devicescomprises a second side comprising second side surfaces of the firstsubstrate, the second substrate and the frit seal, wherein the methodfurther comprises applying the material with the second sides of thefirst and second devices.
 25. The method of claim 1, further comprisingproviding at least one additional device comprising: a first substratecomprising a first side surface, a second substrate comprising a firstside surface and opposing the first substrate, an array of organic lightemitting pixels interposed between the first and second substrates, afrit seal interposed between the first substrate and the secondsubstrate while surrounding the array, wherein the frit seal, the firstsubstrate and the second substrate together define an enclosed space inwhich the array is located, the frit seal comprising a first sidesurface, and a first side comprising the first side surfaces of thefirst substrate, the second substrates and the frit seal; whereinarranging further arranges the at least one additional device togetherwith the first and second devices; wherein applying further applies thematerial on the at least one additional device; and wherein curing formsat least one additional structure, each of which contacts the first sideof each of the at least one additional device.
 26. The method of claim1, wherein the frit seal comprises one or more materials selected fromthe group consisting of magnesium oxide (MgO), calcium oxide (CaO),barium oxide (BaO), lithium oxide (Li₂O), sodium oxide (Na₂O), potassiumoxide (K₂O), boron oxide (B₂O₃), vanadium oxide (V₂O₅), zinc oxide(ZnO), tellurium oxide (TeO₂), aluminum oxide (Al₂O₃), silicon dioxide(SiO₂), lead oxide (PbO), tin oxide (SnO), phosphorous oxide (P₂O₅),ruthenium oxide (Ru₂O), rubidium oxide (Rb₂O), rhodium oxide (Rh₂O),ferrite oxide (Fe₂O₃), copper oxide (CuO), titanium oxide (TiO₂),tungsten oxide (WO₃), bismuth oxide (Bi₂O₃), antimony oxide (Sb₂O₃),lead-borate glass, tin-phosphate glass, vanadate glass, andborosilicate.